why does it say to put a damp cloth over dough, when being left to rise, in recipes

[tweenyb]

just one of those things you see in lots of bread and dough recipes but why?
never seen this happen when i was a nipper working in a bakery so wondered what the point of it was?

[pastafreak]

It will develop a 'skin' if not covered. You want to keep the dough slightly damp.

[Bimbo2010]

But putting clingfilm over does the job too. although not against the surface of the dough.

[jomifl]

I put an inverted bowl over the dough, it is far better than a cloth. If you don't prevent the dough from forming a dry skin you will get a very hard crust.

[tweenyb]

cool, thats excellent thank you.... its awful wondering something and after several years of thinking i must find out, now i know :0)
cheers all xx